Input and Output Devices

Input and Output Devices Input devices:
Input devices are simply the components that a person uses get data into a computer. The most basic input devices are a mouse and keyboard. Keyboards:
In the following image, you can see a keyboard with a relatively standard 104 button layout.

The next two keyboards are 'multimedia' keyboards. They are designed to allow quick access to various options through special buttons. The keyboard immediately below is a standard straight layout that you'll see on most keyboards. The second keyboard has the 'natural' layout. For many people, it is much more comfortable. At first it may look strange but it takes very little time to get used to it.

In the following paragraph, there is a link that will produce a pop-up window. When you're finished viewing the image in the pop-up window, click the X in the top corner of that window. If you don't close it and another window needs to be displayed, the new window may not be visible. The Mouse:
The following image is a Microsoft mouse. As you can see it has 2 visible buttons and a center-mounted scroll wheel. The left button is used to select various objects on the screen, The right button will bring up a dialog box to allow you to select several other options/functions. As I said before, this mouse has 2 'visible' buttons. It also has a 3rd button. It's located 'under' the wheel. If you press the wheel down, the mouse produces a third function. There are typically several selectable functions for the center button. I usually set it todouble-click The 'wheel' on the mouse is typically for scrolling down a page but its function can change depending on the application (program) you're running. For example, if you're watching a video, the scroll may act as a volume control (since there is no need to scroll in a video). Sometimes, the software allows you to select the function of the wheel (volume, zoom, fast-forward/rewind speed...). This is a very basic mouse. There are others that have many more features. The Logitech G500 is one example. You can download the owner's manual [ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]HERE to see what's available on a more advanced mouse. These are mainly purchased for gaming (playing video games on your computer) but can be used like a normal mouse for normal computer operation.

Above, notice that the mouse has a rather large adapter plug on it. This is a USB mouse and I didn't want to take up one of the few USB ports on the computer so I used the adapter. This allowed it to be plugged into the PS/2 port. If you wanted to connect the mouse to a USB port, you'd unplug it from the adapter and plug it directly into the USB port. I'll cover the different types of ports later in the tutorial. In the next image, you can see the bottom of two mice (mouses?). The one on the left is the older style mouse that uses a rubber coated metallic ball to transmit movement to the electronics inside the mouse. The mouse on the right is a newer style 'optical' mouse. To sense motion, the mouse uses an optical sensor. The surface on which the mouse is sitting is illuminated by the red LED. When the mouse is moved, the optical sensor can 'see' the motion and moves the cursor (on the screen) accordingly. The optical system is generally better (no need to periodically clean the ball and the rollers in the mouse). The Microsoft mouse shown is the best I've found. The fit (to my hand) and way the controls function/feel is perfect for me. When you go to buy a mouse, I'd recommend that you do so in a retail outlet that has them displayed (out of the box/packaging). The size and shape of the mouse are possibly the most important aspects of the mouse. All will function as they should but some can be uncomfortable to use for extended periods.

Note: If the top surface of your desk is featureless or is covered with a thick piece of glass, an optical mouse may not work properly. To use an optical mouse on that type of surface, you will need to use some sort of mousepad. A mousepad is typically a smooth neoprene backed mat that's approximately 8" x 8". The surface is designed to make the mouse move smoothly and it typically has a texture that allows an optical mouse to work properly. Wireless Keyboards and Mice:
Wireless keyboards and mice are also available. I didn't like the weight of the earlier wireless mice (batteries increased the weight and the older ones had a heavy metal ball) but the newer ones like the M215 from Logitech are lighter than my wired Microsoft mouse (I still prefer the Microsoft mouse). Many people prefer wireless mice because they don't like having a cable on the mouse (something that's a valid issue for someone using it with a laptop computer). The older ones had a large module that plugged into the PS/2 ports. The newer ones have a small receiver that plugs into a USB port. Other than having to replace the batteries, and possibly having interference with the signal between the device and the receiver (and sometimes an on/of switch), they operate just like normal mice and keyboards. If you're just beginning to use a computer, I'd strongly recommend using a standard hard-wired mouse and keyboard. Even though the wireless devices are reliable, their added complexity could make it more difficult to troubleshoot problems if they don't work properly or quit working properly.

Output Devices:

Output devices are simply the devices that allow you to 'see' the data being produced by the computer. The most basic output device is the monitor. The printer is also an output device. For early computers, printers or plotters were the only output devices. Keyboard Basics:
The following are basic key functions. Most people already know this but I've found a few that didn't so I'll cover it briefly.

The CTRL Key:
The 'control' key provides extended operations to several of the keys. In the following image, you can see many of the most common functions. To activate the function, you press and hold the control key and hit the appropriate button. For example, if you want to copy something, you would press and hold the control key and hit the 'c' on the keyboard (then release both buttons).

F1:
The F1 button is almost universally the 'help' button. Pressing it will bring up the help dialog box for the program you're currently using.

Shift:
The Shift key gives you the upper-case of whatever key is pressed while you're holding the shift key down. It also gives you the characters above the numbers that lie along the top of the letters on the keyboard.

Cap Lock:
The Caps Lock key makes all letters that you type appear in upper-case form. It does not, however give you the characters above the numbers as the shift key does.

Delete:
When pressed, the delete key deletes the character just to the 'right' of the cursor.

Backspace:
When pressed, the backspace key deletes the character just to the 'left' of the cursor.

Scroll Lock:
This button is not used much anymore and only works in a few programs. The only program that I have that uses it is Excel. In Excel, if the scroll lock is ON, the arrow keys can be used to scroll the page without changing the 'active' or highlighted cell.

Number Lock:
When active, this enables the numbers on the keypad. When the num-lock is not enabled, the numbers act the same as the keyboard 'arrows'. The indicator lamp on the keyboard will let you know if it's on or off.

Start:
On newer keyboards, you will have a 'Windows' button. It opens the start menu.

Alt:
The Alt button acts similarly to the Ctrl button. It provides extended functions to some of the keys. For example, the 'PrtScn' button copies the screen to the clipboard (to be covered later). If you use Alt-PrtScn, you will copy only the active window to the clipboard. The Alt-PrtScn function is how I captured many of the sample windows in this tutorial.

Page Up/Page Down:
These buttons scroll one full screen at a time.

Home/End:
These buttons send the text cursor to the left or the right of the line of text in which your text cursor is flashing. This only works in editable text areas.

Note: The keyboard shown above has functions not available on a standard keyboard. The 'F' keys on most keyboards don't perform functions such as 'Undo' and 'Redo'. Cleaning a Ball-Type Mouse:
On the ball-type mice, you will eventually have problems with tracking. Assuming that nothing on your desktop has changed, the problem will likely be that the rollers inside the mouse have become contaminated. The rollers transfer motion from the ball to the encoders. When they get dirty, they fail to roll properly and therefore, the encoders will not 'see' the motion properly. Luckily, the problem is easily corrected. What you need to do is remove the ball retaining cover. It typically either slides off or unscrews ~1/4 turn. There should be some sort of arrow on the cover to tell you what to do. When you remove the cover, the ball will be free to fall out (just letting you know so you don't have to bend down and pick it up off of the floor). When you get it open, you will see three rollers. Two of the rollers are active. The third is spring-loaded and is used to keep the ball in contact with the other rollers. All three rollers need to be free of foreign material. If you look at the following picture (a little disgusting, I know), you can see that the black roller has some gray material on it. It's a combination of cloth and paper fibers and oil from the users hands. To clean it, use a dry paper towel and wipe sideways while rolling the roller a little on each pass. It may take quite a few passes to get it clean. When you think it's clean, turn it by hand and make sure that it is actually clean. Do this on all three rollers. When finished, simply replace the ball and the retainer cover.